Clinical and morphologic findings are described in a 62-year-old woman who had idiopathic dilated cardiomyopathy and at necropsy was found to have unsuspected scarring of the right and left ventricles. Although extensive scarring of the left ventricle has been occasionally described in such patients, it is uncommon. Right ventricular scarring, however, has never before been described. Shortly prior to death this patient manifested signs of pericardial heart disease, yet at necropsy the pericardium was normal. This report points out the manner in which right ventricular scarring in patients with idiopathic dilated cardiomyopathy may mimic pericardial heart disease.